To save money, U.S. airlines are circulating less fresh air into the cabins of many airplanes. As a result, flight attendants and some passengers have begun to complain of headaches, nausea and other health problems, especially after long flights.
The reduction of fresh air is done only on newer planes. Older aircraft built before the mid-1980s provided cabins with 100 percent fresh air that was circulated every three minutes.
But the newer models provide half fresh air and half recirculated air that is freshened every six or seven minutes or longer. The recirculation system enables the planes to use less fuel to cool the outside air, which is heated by the engines as it is drawn in.
"Ventilation systems are driven by air that comes off the engines," said Jack Gamble, the chief spokesman for Boeing, which uses recirculation systems on its newer planes. "If you cut back on the engine system, cut back on the speed, burn less fuel, you're going to cut back on the amount of air circulating in the cabin."
Airline officials say they have received no significant increase in passenger complaints. They also say there is no conclusive correlation between cabin air and the health of passengers.
But Doris Bachrach, a Manhattan securities analyst and frequent traveler, said that in the past two years she had experienced severe headaches on domestic flights of more than four hours. On a recent round trip from New York's Kennedy airport to San Francisco aboard American Airlines, she said, "Both ways, I walked off with a headache. . . ."